做什么?一个人吃饭会影响他的精子和后代?

做什么?一个人吃饭会影响他的精子和后代?

A previously discredited evolutionary theory, called Lamarckism, is being revived thanks to a new understanding of heredity called “epigenetic inheritance”.

在1809,法国进化论者让 - 巴蒂斯特·拉马克提出了收购的性状可以传递到下一代的理论。 他的理论暗示了我们的健康是我们的祖先所选择的生活方式长期我们自身的存在之前确定。 而我们的最新研究补充了这一长期被忽视的理论的可信度。

Lamarck Revisited

Since Lamarck proposed his theory, the transmission of acquired traits has been demonstrated in plants and insects. The phenomenon was thought to be restricted to these species but in 2005, 一项研究 of inhabitants from a remote village in northern Sweden provided evidence that the theory could be extended to humans.

The study showed that inhabitants were less prone to developing cardiometabolic diseases, such as type 2 diabetes, if their respective grandparent of the same sex (that is, grandfathers for men and grandmothers for women) was relatively undernourished in his or her early life.

The study implied that the eating pattern of parents, long before conception, may affect the developmental message contained in their gametes (sperm or egg) and influence the health of the following generations.

The Message Is Carried In Sperm

In 我们的研究, we wanted to know whether nutritional status could change the heritable information contained in gametes.

We focused on sperm rather than eggs because it is easier to collect. We collected sperm from 13 lean and ten obese Danish men and compared their epigenetic imprint (chemical tags to the genome that change the expression of genes without changing the DNA code itself).

We found that numerous epigenetic marks were changed in the sperm of obese men and, most strikingly, they were close to the genes crucial for brain development and the regulation of appetite.

In a second group of six obese men undergoing bariatric surgery (surgery to reduce the size of the stomach), we compared sperm from patients before, one week after and one year after the surgery. At the one-year follow-up visit, the men had lost 30kg, on average, and their metabolic profile had dramatically improved.

When we analysed their sperm, we found that the distribution of the epigenetic tags on genes controlling the regulation of appetite was dramatically remodelled. In other words, weight loss did not change the person’s DNA but it did redistribute the epigenetic marks in the genome specialised in “appetite control”.

Notably, this remodelling of the epigenetic fingerprint occurred on the gene encoding the melanocortin receptor, which senses a key hormone in the regulation of hunger and satiety. So we concluded that sperm from obese men contain specific, and potentially heritable, epigenetic information that could change eating behaviour in offspring.

These findings reinforce the idea that environmental factors change epigenetic information contained in our gametes and could affect the eating behaviour and obesity risk of our children. Although the sample size was small, the statistical significance was strong.

The History Of My Son’s Ancestors

A personal note related to this: the day after my son was born, as I was holding him in my arms, I could not help myself from thinking about his biological inheritance. Almost a hundred years ago, in February 1916, his great-grandfather was lunging, starving, in the hell of the battlefield of Verdun in the north-east of France.

My son’s ancestor experienced famines during the world wars. And, unlike hundreds of thousand of other young soldiers, he survived the war, returned to his small village in the south of France and eventually established his bloodline.

Did the various famines of the past century have an effect on his biology? Also, had the increase in food abundance of the past 60 years had an effect on his health? This thought triggered a sudden burst of anxiety.

However, while staring into my newborn son’s eyes that could barely open in the crude light of the maternity ward, I reassured myself. Thanks to the progress of science, my son will belong to the first generation of people who will be fully aware of the power they hold on the biological fate of their children. Compared with his predecessors, he will live more free to govern, if not his own destiny, then at least the destiny of his offspring.

关于作者谈话

barrres romainRomain Barrès, Associate Professor, epigenetics, University of Copenhagen. He was involved in the first study showing epigenetic inheritance of a obesity (Ng, et al., Nature 2010).

本文最初发表于 谈话。 阅读 原创文章.

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Genetic Memory

作者: Tim Dunn
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